Re: [RFC] WIP: import gpio-poweroff driver from linux kernel

[Sascha Hauer <s.hauer@pengutronix.de>]

Hi Antony,

On Fri, Nov 08, 2019 at 02:56:45PM +0300, Antony Pavlov wrote:
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  drivers/reset/Kconfig         |  7 +++
>  drivers/reset/Makefile        |  1 +
>  drivers/reset/gpio-poweroff.c | 86 +++++++++++++++++++++++++++++++++++
>  3 files changed, 94 insertions(+)
> 
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 048f2081f8..21b61e036f 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -26,4 +26,11 @@ config RESET_STM32
>  	help
>  	  This enables the reset controller driver for STM32MP and STM32 MCUs.
>  
> +config RESET_GPIO_POWEROFF
> +	bool "GPIO power-off driver"
> +	help
> +	  This driver supports turning off your board via a GPIO line.
> +	  If your board needs a GPIO high/low to power down, say Y and
> +	  create a binding in your devicetree.
> +
>  endif
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index 8460c4b154..efd9c951f3 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -2,3 +2,4 @@ obj-$(CONFIG_RESET_CONTROLLER) += core.o
>  obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
>  obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
>  obj-$(CONFIG_RESET_STM32) += reset-stm32.o
> +obj-$(CONFIG_RESET_GPIO_POWEROFF) += gpio-poweroff.o
> diff --git a/drivers/reset/gpio-poweroff.c b/drivers/reset/gpio-poweroff.c
> new file mode 100644
> index 0000000000..89f9ff69c5
> --- /dev/null
> +++ b/drivers/reset/gpio-poweroff.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Toggles a GPIO pin to power down a device
> + *
> + * Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
> + *
> + * Based on linux/drivers/power/reset/gpio-poweroff.c
> + *
> + * Jamie Lentin <jm@lentin.co.uk>
> + * Andrew Lunn <andrew@lunn.ch>
> + *
> + * Copyright (C) 2012 Jamie Lentin
> + */
> +
> +#include <common.h>
> +#include <errno.h>
> +#include <init.h>
> +#include <gpio.h>
> +#include <of_gpio.h>
> +#include <poweroff.h>
> +
> +/*
> + * Hold configuration here.
> + * Cannot be more than one instance of the driver.
> + */
> +static int reset_gpio;
> +
> +static void gpio_poweroff_do_poweroff(struct poweroff_handler *handler)
> +{
> +	shutdown_barebox();
> +
> +	/* drive it active, also inactive->active edge */
> +	gpio_direction_output(reset_gpio, 1);
> +	mdelay(100);
> +	/* drive inactive, also active->inactive edge */
> +	gpio_set_value(reset_gpio, 0);
> +	mdelay(100);
> +
> +	/* drive it active, also inactive->active edge */
> +	gpio_set_value(reset_gpio, 1);
> +
> +	/* give it some time */
> +	mdelay(3000);
> +
> +	WARN_ON(1);
> +	unreachable();
> +}
> +
> +static int __init gpio_poweroff_probe(struct device_d *dev)
> +{
> +	int ret, reset_gpio;
> +	enum of_gpio_flags flags;
> +
> +	if (!IS_ENABLED(CONFIG_OFDEVICE) || !IS_ENABLED(CONFIG_OF_GPIO))
> +		return -ENODEV;

You could use depends on in Kconfig. No need to compile in a driver
which doesn't work.

> +
> +	reset_gpio = of_get_named_gpio_flags(dev->device_node, "gpios", 0, &flags);

As flags are unused, use of_get_named_gpio()?

> +	if (reset_gpio < 0) {
> +		if (reset_gpio != -EPROBE_DEFER)
> +			dev_err(dev, "failed to get gpio for %s: %d\n",
> +				dev->device_node, reset_gpio);
> +		return reset_gpio;
> +	}
> +
> +	ret = gpio_request(reset_gpio, "gpio_poweroff");
> +	if (ret) {
> +		pr_err("gpio_poweroff: (%d) can not be requested\n", reset_gpio);

dev_err please.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox